Update and constant arrays

Hi all, I've updated Pas6502 again.

• I fixed a bug where you could write to a const array!
• I've also added new types of constant arrays you can use. 
  
  As well as the standard fixed-size array, you can define a constant array just using its data, or using for-loop data now!!
  
  The last one was the most difficult, but I got it working...very useful!
  
  The for-loop variable is only defined in the loop and doesn't have to be defined anywhere else :)

  // open array defined by it’s values
  a2 : array of Word = (1,4,3,2,5,76,5,4,2,3);

  // open array defined by a for-loop with an expression
  screenOffset : array of Word = for y := 0 to SCREEN_HEIGHT - 1 do (y*40);